Systems and methods for establishing multiple radio connections

ABSTRACT

A method for establishing multiple radio connections by a user equipment (UE) is described. The method includes receiving a first physical downlink control channel (PDCCH) that includes a first cyclic redundancy check (CRC) scrambled by a first cell radio network temporary identifier (C-RNTI) in a primary radio connection. The method also includes decoding the first PDCCH. The method also includes receiving a second PDCCH that includes a second CRC scrambled by a second C-RNTI in a secondary radio connection. The method also includes decoding the second PDCCH.

RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.15/247,895 entitled “SYSTEMS AND METHODS FOR ESTABLISHING MULTIPLE RADIOCONNECTIONS,” filed Aug. 25, 2016, which is a continuation of U.S.patent application Ser. No. 14/731,188 entitled “SYSTEMS AND METHODS FORESTABLISHING MULTIPLE RADIO CONNECTIONS,” filed Jun. 4, 2015, now U.S.Pat. No. 9,433,027, issued Aug. 30, 2016, which is a continuation ofU.S. patent application Ser. No. 13/849,410 entitled “SYSTEMS ANDMETHODS FOR ESTABLISHING MULTIPLE RADIO CONNECTIONS,” filed Mar. 22,2013, now U.S. Pat. No. 9,078,241, issued Jul. 7, 2015, which are allhereby incorporated by reference in their entirety.

TECHNICAL FIELD

The present disclosure relates generally to communication systems. Morespecifically, the present disclosure relates to systems and methods forestablishing multiple radio connections.

BACKGROUND

Wireless communication devices have become smaller and more powerful inorder to meet consumer needs and to improve portability and convenience.Consumers have become dependent upon wireless communication devices andhave come to expect reliable service, expanded areas of coverage andincreased functionality. A wireless communication system may providecommunication for a number of wireless communication devices, each ofwhich may be serviced by a base station. A base station may be a devicethat communicates with wireless communication devices.

As wireless communication devices have advanced, improvements incommunication capacity, speed, flexibility and efficiency have beensought. However, improving communication capacity, speed, flexibilityand efficiency may present certain problems.

For example, wireless communication devices may communicate with one ormore devices using a communication structure. However, the communicationstructure used may offer limited flexibility and efficiency. Asillustrated by this discussion, systems and methods that improvecommunication flexibility and efficiency may be beneficial.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram illustrating one configuration of one or moreevolved Node Bs (eNBs) and one or more user equipments (UEs) in whichsystems and methods for establishing multiple radio connections may beimplemented;

FIG. 2 is a flow diagram illustrating one configuration of a method forestablishing multiple radio connections by a UE;

FIG. 3 is a flow diagram illustrating one configuration of a method forestablishing multiple radio connections by an eNB;

FIG. 4 is a thread diagram illustrating one configuration of anon-contention based random access procedure;

FIG. 5 is a thread diagram illustrating one configuration of acontention-based random access procedure;

FIG. 6 is a flow diagram illustrating another configuration of a methodfor establishing multiple radio connections by a UE;

FIG. 7 is a flow diagram illustrating another configuration of a methodfor establishing multiple radio connections by an eNB;

FIG. 8 is a block diagram illustrating one configuration of an EvolvedUniversal Terrestrial Radio Access Network (E-UTRAN) architecture inwhich systems and methods for establishing multiple radio connectionsmay be implemented;

FIG. 9 is a block diagram illustrating one configuration of a user planeprotocol stack;

FIG. 10 is a block diagram illustrating one configuration of a controlplane protocol stack;

FIG. 11 is a block diagram illustrating a carrier aggregationconfiguration in which a first cell and a second cell are co-located,overlaid and have approximately equal coverage;

FIG. 12 is a block diagram illustrating a carrier aggregationconfiguration in which a first cell and a second cell are co-located andoverlaid, but the second cell has smaller coverage;

FIG. 13 is a block diagram illustrating a carrier aggregationconfiguration in which a first cell and a second cell are co-located,but the second cell antennas are directed to the cell boundaries of thefirst cell;

FIG. 14 is a block diagram illustrating a carrier aggregationconfiguration in which a first cell provides macro coverage and in whichremote radio heads (RRH) on a second cell are used to improve throughputat hotspots;

FIG. 15 is a block diagram illustrating a carrier aggregationconfiguration in which frequency selective repeaters are deployed;

FIG. 16 is a block diagram illustrating multiple coverage scenarios forsmall cells with and without macro coverage;

FIG. 17 is a block diagram illustrating one configuration of an E-UTRANand a UE in which systems and methods for establishing multiple radioconnections may be implemented;

FIG. 18 is a thread diagram illustrating one configuration of eNBs and aUE in which systems and methods for establishing multiple radioconnections may be implemented;

FIG. 19 is a thread diagram illustrating another configuration of eNBSand a UE in which systems and methods for establishing multiple radioconnections may be implemented;

FIG. 20 illustrates various components that may be utilized in a UE;

FIG. 21 illustrates various components that may be utilized in an eNB;

FIG. 22 is a block diagram illustrating one configuration of a UE inwhich systems and methods for establishing multiple radio connectionsmay be implemented; and

FIG. 23 is a block diagram illustrating one configuration of an eNB inwhich systems and methods for establishing multiple radio connectionsmay be implemented.

DETAILED DESCRIPTION

A method for establishing multiple radio connections by a UE isdescribed. The method includes receiving a first physical downlinkcontrol channel (PDCCH) that includes a first cyclic redundancy check(CRC) scrambled by a first C-RNTI in a primary radio connection. Themethod also includes decoding the first PDCCH. The method also includesreceiving a second PDCCH that includes a second CRC scrambled by asecond C-RNTI in a secondary radio connection. The method also includesdecoding the second PDCCH.

The UE may be configured with a primary radio connection and at leastone secondary radio connection. The method may include at least one ofreceiving an assigned C-RNTI and updating a C-RNTI. The second C-RNTImay be included in a connection control message. The second C-RNTI maybe included in a RRC connection reconfiguration message.

A method for establishing multiple radio connections by an eNB isdescribed. The method includes assigning a second C-RNTI for a secondaryradio connection to a UE that has a first C-RNTI for a primary radioconnection. The method also includes transmitting a second PDCCH thatincludes a second CRC scrambled by the second C-RNTI in a secondaryradio connection.

The method may include storing at least one C-RNTI corresponding to atleast one UE. The method may also include managing the at least oneC-RNTI.

The at least one C-RNTI may include at least one of a C-RNTI for a UEconnected as a primary radio connection and a C-RNTI for a UE connectedas a secondary radio connection.

The second C-RNTI may be included in a connection control message. Thesecond C-RNTI may be included in a RRC connection reconfigurationmessage.

A UE for establishing multiple radio connections is described. The UEincludes a processor and memory in electronic communication with theprocessor. Instructions stored in the memory are executable to receive afirst PDCCH that includes a first CRC scrambled by a first C-RNTI in aprimary radio connection. The instructions are also executable to decodethe first PDCCH. The instructions are also executable to receive asecond PDCCH that includes a second CRC scrambled by a second C-RNTI ina secondary radio connection. The instructions are further executable todecode the second PDCCH.

An eNB for establishing multiple radio connections is described. The eNBincludes a processor and memory in electronic communication with theprocessor. Instructions stored in the memory are executable to assign asecond C-RNTI for a secondary radio connection to a UE that has a firstC-RNTI for a primary radio connection. The instructions are alsoexecutable to transmit a second PDCCH that includes a second CRCscrambled by the second C-RNTI in a secondary radio connection.

The 3rd Generation Partnership Project, also referred to as “3GPP,” is acollaboration agreement that aims to define globally applicabletechnical specifications and technical reports for third and fourthgeneration wireless communication systems. The 3GPP may definespecifications for next generation mobile networks, systems and devices.

3GPP Long Term Evolution (LTE) is the name given to a project to improvethe Universal Mobile Telecommunications System (UMTS) mobile phone ordevice standard to cope with future requirements. In one aspect, UMTShas been modified to provide support and specification for the EvolvedUniversal Terrestrial Radio Access (E-UTRA) and E-UTRAN.

At least some aspects of the systems and methods disclosed herein may bedescribed in relation to the 3GPP LTE, LTE-Advanced (LTE-A) and otherstandards (e.g., 3GPP Releases 8, 9, 10, 11 and/or 12). However, thescope of the present disclosure should not be limited in this regard. Atleast some aspects of the systems and methods disclosed herein may beutilized in other types of wireless communication systems.

A wireless communication device may be an electronic device used tocommunicate voice and/or data to a base station, which in turn maycommunicate with a network of devices (e.g., a public switched telephonenetwork (PSTN), the Internet, etc.). In describing systems and methodsherein, a wireless communication device may alternatively be referred toas a mobile station, a UE, an access terminal, a subscriber station, amobile terminal, a remote station, a user terminal, a terminal, asubscriber unit, a mobile device, etc. Examples of wirelesscommunication devices include cellular phones, smart phones, personaldigital assistants (PDAs), laptop computers, netbooks, e-readers,wireless modems, etc. In 3GPP specifications, a wireless communicationdevice is typically referred to as a UE. However, as the scope of thepresent disclosure should not be limited to the 3GPP standards, theterms “UE” and “wireless communication device” may be usedinterchangeably herein to mean the more general term “wirelesscommunication device.”

In 3GPP specifications, a base station is typically referred to as aNode B, an eNB, a home enhanced or evolved Node B (HeNB) or some othersimilar terminology. As the scope of the disclosure should not belimited to 3GPP standards, the terms “base station,” “Node B,” “eNB,”and “HeNB” may be used interchangeably herein to mean the more generalterm “base station.” Furthermore, one example of a “base station” is anaccess point. An access point may be an electronic device that providesaccess to a network (e.g., Local Area Network (LAN), the Internet, etc.)for wireless communication devices. The term “communication device” maybe used to denote both a wireless communication device and/or a basestation.

It should be noted that as used herein, a “cell” may be anycommunication channel that is specified by standardization or regulatorybodies to be used for International Mobile Telecommunications-Advanced(IMT-Advanced) and all of it or a subset of it may be adopted by 3GPP aslicensed bands (e.g., frequency bands) to be used for communicationbetween an eNB and a UE. “Configured cells” are those cells of which theUE is aware and is allowed by an eNB to transmit or receive information.“Configured cell(s)” may be serving cell(s). The UE may receive systeminformation and perform the required measurements on all configuredcells. “Configured cell(s)” may consist of a primary cell and no, one,or more secondary cell(s). “Activated cells” are those configured cellson which the UE is transmitting and receiving. That is, activated cellsare those cells for which the UE monitors the PDCCH and in the case of adownlink transmission, those cells for which the UE decodes a physicaldownlink shared channel (PDSCH). “Deactivated cells” are thoseconfigured cells that the UE is not monitoring the transmission PDCCH.It should be noted that a “cell” may be described in terms of differingdimensions. For example, a “cell” may have temporal, spatial (e.g.,geographical) and frequency characteristics.

As used herein, the term “connection” may refer to a communication linkbetween a UE and an E-UTRAN. As used herein, the terms “radioconnection,” “connection,” “radio interface” and “interface” may be usedinterchangeably.

The systems and methods disclosed herein describe devices forestablishing multiple radio connections. This may be done in the contextof an E-UTRAN. For example, the systems and methods disclosed herein mayestablish multiple radio connections between a UE and two or more eNBson an E-UTRAN. In one configuration, the two or more eNBs may havedifferent schedulers.

The systems and methods described herein may enhance carrieraggregation. In carrier aggregation, two or more component carriers maybe aggregated in order to support wider transmission bandwidths (e.g.,up to 100 megahertz (MHz)). In one example, carrier aggregation may beused to increase the effective bandwidth available to a UE. Intraditional carrier aggregation, a single eNB may be assumed to providemultiple serving cells for a UE. Even in scenarios where two or morecells may be aggregated (e.g., a macro cell aggregated with remote radiohead (RRH) cells), the cells may be controlled (e.g., scheduled) by asingle eNB. However, in a small cell deployment scenario, each node(e.g., eNB, RRH, etc.) may have its own independent scheduler. Toutilize the radio resources of both nodes efficiently, a UE may connectto two or more nodes that have different schedulers.

In one configuration, for a UE to connect to two nodes (e.g., eNBs) thathave different schedulers, multi-connectivity between the UE and theE-UTRAN may be utilized. For example, in addition to Rel-11 operation, aUE operating according to the Rel-12 standard may be configured withmulti-connectivity (which may be referred to as dual connectivity,inter-eNB carrier aggregation, multi-flow, multi-cell cluster, multi-Uu,etc.). The UE may connect to the E-UTRAN with multiple Uu interfaces, ifconfigured to do so. For instance, the UE may be configured to establishone or more additional radio interfaces (e.g., radio connections) byusing one radio interface (e.g., radio connection). Hereafter, one nodemay be called a primary eNB (PeNB) and another node may be called asecondary eNB (SeNB).

In a multi-connectivity scenario, radio resource managementfunctionality may be located in each node of the E-UTRAN. Accordingly,one node may have some freedom on how to configure the UE. For example,resources (e.g., scheduling, random access resource and C-RNTIs) for anode may need to be able to be managed by the node. Establishingmultiple radio connections, as described in the systems and methodsdisclosed herein, may utilize radio resources of both nodes efficiently.

Various examples of the systems and methods disclosed herein are nowdescribed with reference to the Figures, where like reference numbersmay indicate functionally similar elements. The systems and methods asgenerally described and illustrated in the Figures herein could bearranged and designed in a wide variety of different implementations.Thus, the following more detailed description of severalimplementations, as represented in the Figures, is not intended to limitscope, as claimed, but is merely representative of the systems andmethods.

FIG. 1 is a block diagram illustrating one configuration of one or moreevolved Node Bs (eNBs) 160 and one or more user equipments (UEs) 102 inwhich systems and methods for establishing multiple connections may beimplemented. The one or more UEs 102 may communicate with one or moreeNBs 160 using one or more antennas 122 a-n. For example, a UE 102 maytransmit electromagnetic signals to the eNB 160 and may receiveelectromagnetic signals from the eNB 160 using the one or more antennas122 a-n. The eNB 160 may communicate with the UE 102 using one or moreantennas 180 a-n. It should be noted that one or more of the UEsdescribed herein may be implemented in a single device in someconfigurations. Additionally or alternatively, one or more of the eNBs160 described herein may be implemented in a single device in someconfigurations. In the context of FIG. 1, for instance, a single devicemay include one or more UEs 102 in accordance with the systems andmethods described herein. Additionally or alternatively, one or moreeNBs 160 in accordance with the systems and methods described herein maybe implemented as a single device or multiple devices.

The UE 102 and the eNB 160 may use one or more channels 119, 121 tocommunicate with each other. For example, a UE 102 may transmitinformation or data to the eNB 160 using one or more uplink channels121. Examples of uplink channels 121 include a physical uplink controlchannel (PUCCH) and a physical uplink shared channel (PUSCH), etc. Theone or more eNBs 160 may also transmit information or data to the one ormore UEs 102 using one or more downlink channels 119, for instance.Examples of downlink channels 119 include a PDCCH, a PDSCH, etc. Otherkinds of channels may be used.

Each of the one or more UEs 102 may include one or more transceivers118, one or more demodulators 114, one or more decoders 108, one or moreencoders 150, one or more modulators 154, a data buffer 104 and a UEoperations module 124. For example, one or more reception and/ortransmission paths may be implemented in the UE 102. For convenience,only a single transceiver 118, decoder 108, demodulator 114, encoder 150and modulator 154 are illustrated in the UE 102, though multipleparallel elements (e.g., transceivers 118, decoders 108, demodulators114, encoders 150 and modulators 154) may be implemented.

The transceiver 118 may include one or more receivers 120 and one ormore transmitters 158. The one or more receivers 120 may receive signalsfrom the eNB 160 using one or more antennas 122 a-n. For example, thereceiver 120 may receive and downconvert signals to produce one or morereceived signals 116. The one or more received signals 116 may beprovided to a demodulator 114. The one or more transmitters 158 maytransmit signals to the eNB 160 using one or more antennas 122 a-n. Forexample, the one or more transmitters 158 may upconvert and transmit oneor more modulated signals 156.

The demodulator 114 may demodulate the one or more received signals 116to produce one or more demodulated signals 112. The one or moredemodulated signals 112 may be provided to the decoder 108. The UE 102may use the decoder 108 to decode signals. The decoder 108 may produceone or more decoded signals 106, 110. For example, a first UE-decodedsignal 106 may comprise received payload data, which may be stored in adata buffer 104. A second UE-decoded signal 110 may comprise overheaddata and/or control data. For example, the second UE-decoded signal 110may provide data that may be used by the UE operations module 124 toperform one or more operations.

As used herein, the term “module” may mean that a particular element orcomponent may be implemented in hardware, software or a combination ofhardware and software. However, it should be noted that any elementdenoted as a “module” herein may alternatively be implemented inhardware. For example, the eNB operations module 182 may be implementedin hardware, software or a combination of both.

In general, the UE operations module 124 may enable the UE 102 tocommunicate with the one or more eNBs 160. The UE operations module 124may include one or more of a UE radio communication determination module128, a random access procedure module 126 and a C-RNTI interpreter 130.

The UE radio connection determination module 128 may establish a primaryradio connection between the UE 102 and a first point on an E-UTRAN. Forexample, the first point may include a first eNB 160 belonging to theE-UTRAN. In one configuration, the first eNB 160 may be a PeNB. Forexample, when a UE 102 is adding a connection, the first point (e.g.,the first eNB 160) may be a PeNB. The UE radio connection determinationmodule 128 may connect to the first point (e.g., the first eNB 160) witha Uu interface. The Uu interface may also be referred to as a primary Uuinterface. The Uu interface may be a radio connection between the UE 102and the PeNB.

The UE 102 may be configured to establish a second radio connectionbetween the UE 102 and a second point on the E-UTRAN. For example, thesecond point may include a second eNB 160 belonging to the E-UTRAN. Inone configuration, the second eNB 160 may be a SeNB, when the UE 102 isadding a connection, for example. In one configuration, the first point(e.g., the first eNB 160) and the second point (e.g., the second eNB160) may have different schedulers. The UE radio connectiondetermination module 128 may connect to the second eNB 160 with a Uuxinterface. The Uux interface may also be referred to as a secondary Uuinterface.

In some configurations, certain procedures may be performed during ahandover procedure between cell(s) in a source SeNB and cell(s) in atarget SeNB. For example, the UE 102 may first connect to the cell(s) inthe source SeNB as a second point. After successfully accessing (via arandom access, for example) the cell(s) in the target SeNB, connectionwith the target SeNB may be complete. The UE 102 may connect to thecell(s) in the target SeNB as the second point. For example, afterreceiving a signal from the target SeNB and transmitting a random accesspreamble, the UE 102 may complete a connection to the cell(s) in thetarget SeNB as the second point. In some implementations, this may be ahandover in a secondary radio connection. In these implementations, apoint may not be added, but rather replaced.

There may be several types of handover procedures for a secondary radioconnection. One example is an intra-cell handover, where a cell in aSeNB may be updated by a handover procedure to the same cell. Anotherexample is an intra-SeNB handover, where a cell in a SeNB may switch toanother cell in the SeNB. Yet another example is an inter-SeNB handover,where a cell in a SeNB may switch to another cell in another SeNB.Accordingly, the target SeNB may or may not be the same with the sourceSeNB.

The UE 102 may not be required to be aware of the PeNB and the SeNB, aslong as the UE 102 is aware of the multiple Uu interfaces with theE-UTRAN. In one configuration, the UE 102 may see an eNB 160 as a pointon the E-UTRAN. In another configuration, the UE 102 may see themultiple Uu interfaces with the E-UTRAN as connections with multiplepoints on the E-UTRAN. In another configuration, the E-UTRAN may providemultiple Uu interfaces with the same or different eNBs 160. Forinstance, the PeNB and the SeNB may be the same eNB 160. The multiple Uuinterfaces (e.g., multi-connectivity) may be achieved by a single eNB160. In other words, in one configuration, the systems and methodsdescribed herein may be achieved by a single eNB 160 or a singlescheduler. The UE 102 may be able to connect more than one Uux interface(e.g., Uu1, Uu2, Uu3, etc.). Each Uu interface may be used to performcarrier aggregation. Accordingly, the UE 102 may be configured with morethan one set of serving cells in a carrier aggregation scenario.

It should be noted that while multiple Uu interfaces are described, thesystems and methods described herein may be realized by a single Uuinterface or a single radio connection depending on the definition ofinterface. For example, a radio interface may be defined as an interfacebetween the UE 102 and the E-UTRAN. In this definition, the interfacemay not be an interface between the UE 102 and the eNB 160. For example,one radio interface may be defined as an interface between the UE 102and the E-UTRAN with multi-connectivity. Accordingly, the Uu interfaceand the Uux interface discussed above may be considered as differentcharacteristics of cells. For instance, the Uu interface may be a firstset of cell(s) and the Uux interface may be a second set of cell(s).Also, the first radio interface may be rephrased as a first set ofcell(s) and the second radio interface may be rephrased as a second setof cell(s).

The random access procedure module 126 may perform a random accessprocedure for a radio connection. For example, the random accessprocedure module 126 may perform a random access procedure for asecondary radio connection. According to some configurations, multiplerandom access procedures may be triggered. In some implementations, therandom access procedure for a radio connection may be a random accessprocedure for another radio connection in parallel or concurrently. Therandom access procedure may be performed for a cell of a radioconnection.

It should be noted that even in a single connectivity configuration,multiple random access procedures may be triggered. However, there maybe only one random access procedure ongoing at any point in time in asingle connectivity configuration. If the UE 102 receives a request fora new random access procedure in a radio connection while another randomaccess procedure is already ongoing in the radio connection, it may beup to the UE 102 to determine whether to continue with the ongoingrandom access procedure or start with the new random access procedure.

An example of a random access procedure may be accessing a target cellvia a random access channel (RACH). The random access procedure module126 may perform different types of random access procedures. Forexample, the random access procedure module 126 may perform anon-contention-based random access procedure. Performing anon-contention-based random access procedure may include utilizing adedicated random access preamble via a random access channel to access atarget cell. In another example, the UE 102 may perform acontention-based random access procedure. An example of acontention-based random access procedure may include accessing a targetcell via a random access channel using a randomly selected preamble.More detail concerning non-contention-based random access procedures andcontention-based random access procedures is given in connection with atleast one of FIGS. 4 and 5.

In some implementations, whether the UE 102 performs a contention-basedrandom access procedure or a non-contention-based random accessprocedure for a secondary radio connection may be based on a receivedmessage. For example, The UE 102 may receive a RRC connectionreconfiguration message that may include a connection control message.The connection control message may indicate whether a dedicated RACHpreamble identity (e.g., a random access preamble identity) is includedin the connection control message (e.g., whether a dedicated RACHpreamble is indicated in the connection control message). If theconnection control message includes a dedicated RACH preamble identity,the UE 102 may perform a non-contention-based random access procedure.By comparison, if the connection control message does not include adedicated RACH preamble identity, the UE 102 may perform acontention-based random access procedure.

An example of performing a random access procedure is given as follows.In response to an RRC connection reconfiguration message including theconnection control message, the UE 102 may perform a random accessprocedure. The RRC connection reconfiguration message (e.g.,RRCConnectionReconfiguration) may carry a handover command (e.g.,MobilityControlInfo (mobility control information)). The RRC connectionreconfiguration message (e.g., RRCConnectionReconfiguration) may alsocarry a connection control message (e.g., ConnectionControlInfo(connection control information)). According to Rel-11 and before, theRRC connection reconfiguration message may have been used for manypurposes, for example, physical layer parameters, media access control(MAC) layer control parameters, and one or more UE 102 configurationparameters, etc. When implemented in accordance with knownspecifications (e.g., Rel-11 and before), the RRC connectionreconfiguration message may be a legacy message. For example, when theRRC connection reconfiguration message includes a handover command, aRACH may be triggered for a single connection. However, it should benoted that the systems and methods described herein introduce aconnection control message in addition to the behaviors of Rel-11 andbefore.

In some implementations, if the RRC connection reconfiguration messageincludes a handover command (e.g., MobilityControlInfo), the UE 102 mayperform a handover procedure. In the handover command, a dedicated RACHpreamble may be included. In response to the RRC connectionreconfiguration message (that includes the handover command), the UE 102may perform a random access procedure. In some implementations, theconnection control message may be different from a handover command. Forexample, a handover command may be used for a handover for a singleradio connection. On the other hand, a connection control message may beused to add a secondary radio connection and/or a handover in thesecondary radio connection.

In carrier aggregation, an addition of a secondary cell may be signaledto the UE 102 by the RRC connection reconfiguration message. However,since the RRC connection reconfiguration message may not include ahandover command, the UE 102 may not trigger a random access procedurein response to the RRC connection reconfiguration message. If necessary,a random access order may be signaled to the UE 102 to achieve an uplinktime alignment in the secondary cell. In case of the addition of thesecondary radio connection, it may be better to trigger a random accessbecause a cell that is newly added may be managed by a differentscheduler and is likely unsynchronized with a cell that is alreadyconfigured for the UE 102.

The C-RNTI interpreter 130 may decode a PDCCH or an EPDCCH. Decoding aPDCCH (or an EPDCCH) may include interpreting the PDCCH (or the EPDCCH).An example is given as follows. The UE 102 may receive a PDCCH thatcarries downlink control information (DCI). DCI in each PDCCH (or eachEPDCCH) may use a DCI format that defines the fields of the DCI. In someimplementations, a Radio Network Temporary Identifier (RNTI) (e.g., aC-RNTI) may be included with the DCI. A RNTI (e.g., a C-RNTI) may beused to identify the UE 102 and identify usage. A RNTI may also be usedin scheduling resources for a radio connection. For a UE configured forsingle connectivity with an E-UTRAN, it should be noted that the UE mayuse the same C-RNTI for all serving cells. In Rel-11 and before, aC-RNTI may be allocated to a UE 102. A RNTI (a C-RNTI, for example) mayhave several usages. Table (1) presents various RNTI values. Table (2)presents various RNTI usages and associated transport channels andlogical channels.

TABLE 1 Value (hexa-decimal) RNTI 0000 N/A 0001-003C Random Access-RNTI(RA-RNTI), C-RNTI, Semi-Persistent Scheduling C-RNTI, Temporary C-RNTI,Transmit Power Control-Physical Uplink Control Channel-RNTI (TPC-PUCCH-RNTI) and Transmit Power Control-Physical Uplink SharedChannel-RNTI (TPC-PUSCH-RNTI) 003D-FFF3 C-RNTI, Semi-PersistentScheduling C-RNTI, Temporary C- RNTI, TPC-PUCCH-RNTI and TPC-PUSCH-RNTIFFF4-FFFC Reserved for future use FFFD Multimedia Broadcast MulticastService RNTI (M-RNTI) FFFE Paging RNTI (P-RNTI) FFFF System InformationRNTI (SI-RNTI)

TABLE 2 Transport Logical RNTI Usage Channel Channel P-RNTI Paging andSystem Information Paging Channel Paging Control change notification(PCH) Channel (PCCH) SI-RNTI Broadcast of System Information DownlinkShared Broadcast Control Channel (DL-SCH) Channel (BCCH) M-RNTIMulticast Control Channel N/A N/A (MCCH) Information change notificationRA-RNTI Random Access Response DL-SCH N/A Temporary ContentionResolution DL-SCH Common Control C-RNTI (when no valid C-RNTI is Channel(CCCH) available) Temporary Msg3 transmission Uplink Shared CCCH,(Dedicated C-RNTI Channel (UL-SCH) Control Channel) DCCH, (DedicatedTraffic Channel) DTCH C-RNTI Dynamically scheduled unicast UL-SCH DCCH,DTCH transmission C-RNTI Dynamically scheduled unicast DL-SCH CCCH,DCCH, DTCH transmission C-RNTI Triggering of PDCCH ordered N/A N/Arandom access Semi- Semi-Persistently scheduled DL-SCH, UL-SCH DCCH,DTCH Persistent unicast transmission Scheduling (activation,reactivation and C-RNTI retransmission) Semi- Semi-Persistentlyscheduled N/A N/A Persistent unicast transmission Scheduling(deactivation) C-RNTI TPC-PUCCH- Physical layer Uplink power N/A N/ARNTI control TPC-PUSCH- Physical layer Uplink power N/A N/A RNTI control

An example of a C-RNTI included in a PDCCH is given as follows. A cyclicredundancy check (CRC) may be included in the DCI. Error detection maybe provided on DCI transmissions through a CRC. In some implementations,the C-RNTI may be implicitly encoded in the CRC. The number of paritybits of the CRC may be 16. The entire payload may be used to calculatethe CRC parity bits. In some configurations, the CRC parity bits may bescrambled with a corresponding RNTI (e.g., a C-RNTI). In other words,the CRC parity bits may be “XORed” with a RNTI. In this example, theC-RNTI interpreter 130 may decode (and interpret) the PDCCH.Interpreting the PDCCH may include separating the CRC parity bits fromthe C-RNTI. In some implementations, a physical (PHY) layer of the UE102 may be configured by a higher layer (e.g., a MAC sublayer or a radioresource control (RRC) sublayer) of the UE 102 to decode the PDCCH (orthe EPDCCH) with a CRC scrambled by the C-RNTI. The DCI may alsotransport downlink or uplink scheduling information, request aperiodicchannel quality information (CQI) reports, send notifications of MCCHchanges and send uplink power control commands for a cell and a RNTI.

In some implementations, the C-RNTI interpreter 130 may decode multiplePDCCHs. For example, in Rel-11 and before, a UE may not have beenconfigured to decode (and interpret) a first PDCCH (or a first EPDCCH)with a first CRC scrambled by a first C-RNTI and to decode (andinterpret) a second PDCCH or (a second EPDCCH) with a second CRCscrambled by a second C-RNTI. However, according to the systems andmethods disclosed herein, in addition to decoding (and interpreting) aPDCCH with a CRC scrambled by a first C-RNTI, the UE 102 may beconfigured to decode (and interpret) a PDCCH with a CRC scrambled by asecond C-RNTI.

An example is given as follows. In Rel-11 and before, a UE may have beenconfigured to monitor or decode PDCCHs in a common search space of aprimary cell (PCell) and a UE 102 specific search space of each servingcell (e.g., PCell and secondary cell(s) (SCell)). A search space may bedefined as a set of candidate PDCCHs (or EPDCCHs) to be decoded. The UEmay also be configured with kinds of DCI formats that should bemonitored or decoded in the search spaces. The UE may be furtherconfigured with kinds of RNTIs (corresponding to a DCI format) thatshould be monitored or decoded in the DCI with a DCI format in eachPDCCH in the search spaces.

In some cases, the UE 102 may be configured to monitor or decode a PDCCHwith a CRC scrambled by a C-RNTI, to monitor or decode a PDCCH with aCRC scrambled by a Temporary C-RNTI, to monitor or decode a PDCCH with aCRC scrambled by a Semi-Persistent Scheduling C-RNTI, etc. When the UEdecodes a PDCCH with a DCI format, the UE may try to match several RNTIsthat are configured to be decoded. The UE may then try to decode PDCCHswith the same or different DCI formats with those RNTIs, until the UEfinishes checking all PDCCHs in the search space. This may be referredto as “blind decoding.” In some implementations, only one C-RNTI may beconfigured for the UE and the C-RNTI may be used to decode PDCCHs withone or more DCI formats. However, according to the systems and methodsdisclosed herein, in addition to the behaviors of Rel-11 and before, theUE 102 may be allocated a second C-RNTI for the secondary radioconnection in addition to the first C-RNTI for the primary radioconnection. In addition to decoding each PDCCH with a CRC scrambled by afirst C-RNTI in a common search space and a UE 102 specific search spaceof each serving cell of the primary connection, the UE 102 may beconfigured to decode each PDCCH with a CRC scrambled by a second C-RNTIin a common search space and a UE 102 specific search space of eachserving cell of the secondary radio connection.

In some implementations, the UE operations module 124 may include one ofthe modules indicated in FIG. 1. For example, in one implementation, theUE operations module 124 may include only the random access proceduremodule 126. In another implementation, the UE operations module 124 mayinclude only the C-RNTI interpreter 130. In other implementations, theUE operations module 124 may include multiple modules indicated in FIG.1, and any combination thereof. For example, the UE 102 may include atleast two of the random access procedure module 126, the C-RNTIinterpreter 130 and the UE radio connection determination module 128.

The UE operations module 124 may provide information 148 to the one ormore receivers 120. For example, the UE operations module 124 may informthe receiver(s) 120 when or when not to receive transmissions based ondownlink scheduling information or a discontinuous reception (DRX)configuration, etc.

The UE operations module 124 may provide information 138 to thedemodulator 114. For example, the UE operations module 124 may informthe demodulator 114 of a modulation pattern anticipated fortransmissions from the eNB 160.

The UE operations module 124 may provide information 136 to the decoder108. For example, the UE operations module 124 may inform the decoder108 of an anticipated encoding for transmissions from the eNB 160.

The UE operations module 124 may provide information 142 to the encoder150. The information 142 may include data to be encoded and/orinstructions for encoding. For example, the UE operations module 124 mayinstruct the encoder 150 to encode transmission data 146 and/or otherinformation 142. The other information 142 may include RRC messages.

The encoder 150 may encode transmission data 146 and/or otherinformation 142 provided by the UE operations module 124. For example,encoding the data 146 and/or other information 142 may involve errordetection and/or correction coding, mapping data to space, time and/orfrequency resources for transmission, multiplexing, etc. The encoder 150may provide encoded data 152 to the modulator 154.

The UE operations module 124 may provide information 144 to themodulator 154. For example, the UE operations module 124 may inform themodulator 154 of a modulation type (e.g., constellation mapping) to beused for transmissions to the eNB 160. The modulator 154 may modulatethe encoded data 152 to provide one or more modulated signals 156 to theone or more transmitters 158.

The UE operations module 124 may provide information 140 to the one ormore transmitters 158. This information 140 may include instructions forthe one or more transmitters 158. For example, the UE operations module124 may instruct the one or more transmitters 158 when to transmit asignal to the eNB 160. The one or more transmitters 158 may upconvertand transmit the modulated signal(s) 156 to one or more eNBs 160.

The eNB 160 may include one or more transceivers 176, one or moredemodulators 172, one or more decoders 166, one or more encoders 109,one or more modulators 113, a data buffer 162 and an eNB operationsmodule 182. For example, one or more reception and/or transmission pathsmay be implemented in an eNB 160. For convenience, only a singletransceiver 176, decoder 166, demodulator 172, encoder 109 and modulator113 are illustrated in the eNB 160, though multiple parallel elements(e.g., transceivers 176, decoders 166, demodulators 172, encoders 109and modulators 113) may be implemented.

The transceiver 176 may include one or more receivers 178 and one ormore transmitters 117. The one or more receivers 178 may receive signalsfrom the UE 102 using one or more antennas 180 a-n. For example, thereceiver 178 may receive and downconvert signals to produce one or morereceived signals 174. The one or more received signals 174 may beprovided to a demodulator 172. The one or more transmitters 117 maytransmit signals to the UE 102 using one or more antennas 180 a-n. Forexample, the one or more transmitters 117 may upconvert and transmit oneor more modulated signals 115.

The demodulator 172 may demodulate the one or more received signals 174to produce one or more demodulated signals 170. The one or moredemodulated signals 170 may be provided to the decoder 166. The eNB 160may use the decoder 166 to decode signals. The decoder 166 may produceone or more decoded signals 164, 168. For example, a first eNB-decodedsignal 164 may comprise received payload data, which may be stored in adata buffer 162. A second eNB-decoded signal 168 may comprise overheaddata and/or control data. For example, the second eNB-decoded signal 168may provide data (e.g., PUSCH transmission data) that may be used by theeNB operations module 182 to perform one or more operations.

In general, the eNB operations module 182 may enable the eNB 160 tocommunicate with the one or more UEs 102 and to communicate with one ormore network nodes (e.g., a mobility management entity (MME), servinggateway (S-GW), eNBs). The eNB operations module 182 may include one ormore of a connection control message management module 194 and a C-RNTImanagement module 196.

The connection control message management module 194 may obtain aconnection control message. In some implementations, obtaining aconnection control message may include receiving a connection controlmessage. For example, a PeNB (or a source SeNB) may receive a connectioncontrol message that was generated by a SeNB (or a target SeNB). Aconnection control message may include connection control informationfor a secondary radio connection. The message structure of theconnection control message may be able to switch whether a dedicatedRACH preamble identity is included or not. For example, the connectioncontrol message may direct the UE 102 to add a new connection or toperform a handover in a secondary radio connection. The connectioncontrol message may be included in the RRC connection reconfigurationmessage.

In another implementation, the connection control message managementmodule 194 may generate a connection control message. For example, aSeNB (or a target SeNB) may generate the connection control message. Aswill be described in connection with at least one of FIGS. 16 and 17,the SeNB (or target SeNB) may generate the connection control messagebased on received information.

The eNB operations module 182 may also generate a RRC connectionreconfiguration message to be signaled to the UE 102. The RRC connectionreconfiguration message may or may not include a handover command and/ora connection control message. For example, the eNB 160 may receive thehandover command and/or the connection control message from another eNBas a transparent container. The eNB 160 may generate a RRC connectionreconfiguration message that may include the received transparentcontainer and may send the RRC connection reconfiguration message to theUE 102.

The C-RNTI management module 196 may obtain a C-RNTI. For example, theC-RNTI management module 196 may obtain a second C-RNTI that correspondsto a secondary radio connection. According to one example, the eNB 160(a PeNB, for example) may receive the C-RNTI from another eNB 160 (aSeNB, for example). In another example, the C-RNTI management module 196may receive the C-RNTI from another device. For example, a SeNB mayreceive the C-RNTI from a network server.

In some implementations, the C-RNTI management module 196 may reserve aC-RNTI for a radio connection. For example, a SeNB may reserve theC-RNTI for a secondary radio connection. The SeNB may then send thereserved C-RNTI in a connection control message. The connection controlmessage including the C-RNTI may be sent to the UE 102 via the RRCconnection reconfiguration message.

In some implementations, the eNB operations module 182 may include oneof the modules indicated in FIG. 1. For example, in one implementation,the eNB operations module 182 may include only the connection controlmessage management module 194. In another example, the eNB operationsmodule 182 may include only the C-RNTI management module 196. In otherimplementations, the eNB operations module 182 may include multiplemodules indicated in FIG. 1. For example, the eNB operations module 182may include the connection control message management module 194 and theC-RNTI management module 196.

The eNB operations module 182 may provide information 190 to the one ormore receivers 178. For example, the eNB operations module 182 mayinform the receiver(s) 178 when or when not to receive transmissions.

The eNB operations module 182 may provide information 188 to thedemodulator 172. For example, the eNB operations module 182 may informthe demodulator 172 of a modulation pattern anticipated fortransmissions from the UE(s) 102.

The eNB operations module 182 may provide information 186 to the decoder166. For example, the eNB operations module 182 may inform the decoder166 of an anticipated encoding for transmissions from the UE(s) 102.

The eNB operations module 182 may provide information 101 to the encoder109. The information 101 may include data to be encoded and/orinstructions for encoding. For example, the eNB operations module 182may instruct the encoder 109 to encode transmission data 105 and/orother information 101. The other information 101 may include RRCmessages.

The encoder 109 may encode transmission data 105 and/or otherinformation 101 provided by the eNB operations module 182. For example,encoding the data 105 and/or other information 101 may involve errordetection and/or correction coding, mapping data to space, time and/orfrequency resources for transmission, multiplexing, etc. The encoder 109may provide encoded data 111 to the modulator 113. The transmission data105 may include network data to be relayed to the UE 102.

The eNB operations module 182 may provide information 103 to themodulator 113. This information 103 may include instructions for themodulator 113. For example, the eNB operations module 182 may inform themodulator 113 of a modulation type (e.g., constellation mapping) to beused for transmissions to the UE(s) 102. The modulator 113 may modulatethe encoded data 111 to provide one or more modulated signals 115 to theone or more transmitters 117.

The eNB operations module 182 may provide information 192 to the one ormore transmitters 117. This information 192 may include instructions forthe one or more transmitters 117. For example, the eNB operations module182 may instruct the one or more transmitters 117 when to (or when notto) transmit a signal to the UE(s) 102. The one or more transmitters 117may upconvert and transmit the modulated signal(s) 115 to one or moreUEs 102.

It should be noted that one or more of the elements or parts thereofincluded in the eNB(s) 160 and UE(s) 102 may be implemented in hardware.For example, one or more of these elements or parts thereof may beimplemented as a chip, circuitry or hardware components, etc. It shouldalso be noted that one or more of the functions or methods describedherein may be implemented in and/or performed using hardware. Forexample, one or more of the methods described herein may be implementedin and/or realized using a chipset, an application-specific integratedcircuit (ASIC), a large-scale integrated circuit (LSI) or integratedcircuit, etc.

FIG. 2 is a flow diagram illustrating one configuration of a method 200for establishing multiple radio connections by a UE 102. The UE 102 mayestablish 202 a primary radio connection between the UE 102 and a firstpoint on an E-UTRAN. For example, a first eNB 160 (e.g., the firstpoint) may belong to the E-UTRAN. In one configuration, the first eNB160 may be a PeNB. The UE 102 may connect to the PeNB with a Uuinterface. In another configuration, the first eNB 160 may be a SeNB.

The UE 102 may receive 204 a connection control message. For example,the UE 102 may receive 204 a RRC connection reconfiguration message(e.g., RRCConnectionReconfiguration message) that may include theconnection control message (e.g., connection control information). Theconnection control message may be used as a connection control for asecondary radio connection. The connection control information mayinclude one or more of a radio bearer configuration for a radioconnection, a C-RNTI for a radio connection, a physical cell identifierfor a cell, a dedicated RACH preamble identity, a security algorithmidentifier, access parameters, system information blocks (SIBs), etc.The UE 102 may receive 204 the connection reconfiguration message from afirst eNB 160 that may be either a PeNB or a source SeNB.

As described above, the connection control message may direct the UE 102to perform at least one of an addition of connection (e.g., a secondaryradio connection) and a handover in a radio connection. For example, theconnection control message may direct the UE 102 to add a new connectionbetween the UE 102 and the E-UTRAN. Adding a connection may includereceiving a C-RNTI assigned for the radio connection. There may beseveral ways to assign a C-RNTI to the UE 102. An example is given asfollows. Initially, a C-RNTI may be assigned in a MAC sublayer. In arandom access procedure, a Temporary C-RNTI may be assigned. In someimplementations, the Temporary C-RNTI may be included in a random accessresponse message. In this implementation, the Temporary C-RNTI may bepromoted to a C-RNTI when the UE 102 detects random access success anddoes not already have a C-RNTI. The C-RNTI may then be dropped byothers. If the UE 102 detects random access success and already has aC-RNTI, the UE 102 may resume using its C-RNTI. For example, when thepurpose of the random access is initial access from an RRC_IDLE state orafter a RRC connection re-establishment procedure, the UE 102 may notalready have a C-RNTI. In this case, a Temporary C-RNTI may be promotedat the success of random access. This step may be performed inaccordance with Rel-11 and before.

In another example, the RRC connection reconfiguration message thatincludes a handover command may direct the UE 102 to perform a handoverin a radio connection. Performing a handover may include updating aC-RNTI of the UE 102. For example, if the UE 102 is in an RRC_CONNECTEDstate, the C-RNTI may be changed (e.g., updated) at a handoverprocedure. A new C-RNTI for a target PCell may be provided in a handovercommand (e.g., MobilityControlInfo) in a source PCell from the eNB 160to the UE 102. This C-RNTI assignment may be done in a RRC sublayer. Inthis example, the UE 102 may have multiple C-RNTIs, but the new C-RNTImay be applied after initializing synchronizing to the downlink of thetarget PCell. This step may be performed in accordance with Rel-11 andbefore. Additionally, in some implementations, a connection controlmessage included in the RRC connection reconfiguration message mayinclude at least one of a C-RNTI for the second radio connection, aphysical cell identifier for a target cell, a security algorithmidentifier and a dedicated RACH preamble identity. This is a newprocedure (for Rel-12 specifications, for example).

The UE 102 may perform a random access procedure for the secondary radioconnection in response to receiving the connection control message. Inresponse to the connection control message, The UE 102 may determine 206if a dedicated RACH preamble is indicated in the connection controlmessage. For example, the connection control message may include aparameter that indicates a dedicated RACH preamble. In a case that theUE 102 determines 206 that a dedicated RACH preamble is indicated in theconnection control message, the UE 102 may perform 208 anon-contention-based random access procedure for the secondary radioconnection. For example, a UE 102 may access a target cell, via theRACH, using a contention-free procedure. By comparison, in a case thatthe UE 102 determines 206 that a dedicated RACH preamble is notindicated in the connection control message, the UE 102 may perform 210a contention-based random access procedure. For example, in response tothe RRC connection configuration message that includes the connectioncontrol message, the UE 102 may perform a random access procedure.

FIG. 3 is a flow diagram illustrating one configuration of a method 300for establishing multiple radio connections by an eNB 160. The eNB 160may establish 302 a radio connection with the UE 102. For example, afirst eNB 160 may belong to an E-UTRAN. In one configuration, the firsteNB 160 may be a PeNB. The first eNB 160 may establish 302 a radioconnection with the UE 102 using a Uu interface as described inconnection with FIG. 1.

The eNB 160 may obtain 304 a connection control message for a secondaryradio connection. The connection control message may indicate whether adedicated RACH preamble is included in the connection control message.The connection control message (included in an RRC connectionreconfiguration message, for example) may also be able to switch whethera dedicated RACH preamble identity is included or not.

In some implementations, obtaining 304 a connection control message mayinclude receiving a connection control message. For example, asdescribed above, a PeNB may receive the connection control message froma SeNB. In this example, the PeNB may send 306 the connection controlmessage to the UE 102 (in a RRC connection reconfiguration message, forexample). Another example of receiving a connection control message (ina RRC connection reconfiguration message, for example) is given asfollows. A PeNB or a source SeNB may receive the connection controlmessage from a target SeNB. In this example, the PeNB or the source SeNBmay generate a RRC connection reconfiguration message including theconnection control message. The PeNB or the source SeNB may then send306 the RRC connection reconfiguration message including the connectioncontrol message to the UE 102.

In some implementations, the connection control message may be used fora handover between cells in a secondary radio connection. For example,the PeNB or the source SeNB may receive a connection control messagefrom the target SeNB (not described in this example because theconnection control message received from the target SeNB can beexchanged or shared between the PeNB and source SeNB). The PeNB or thesource SeNB may send a RRC connection reconfiguration message (includingthe connection control message) to the UE 102 (not shown). In someexamples, the connection control message may not be used. Instead, ahandover command (e.g., MobilityControlInfo) may be used and thehandover command in the secondary radio connection may be included in asecondary RRC connection reconfiguration message which is distinguishedfrom the RRC connection reconfiguration message used in the primaryradio connection. Then, a secondary RRC connection reconfigurationcomplete message may be sent from the UE 102 to the target SeNB as anacknowledgement to the secondary RRC connection reconfiguration message.The secondary RRC connection reconfiguration complete message may bedistinguished from the RRC connection reconfiguration complete messageused in the primary radio connection.

In other implementations, obtaining 304 a connection control message mayinclude generating a connection control message. For example, a SeNB maygenerate the connection control message. The SeNB may generate theconnection control message based on information received from anothereNB (a PeNB, for example). In this example, the SeNB may send 306 theconnection control message to the PeNB. The PeNB may then forward theconnection control message to the UE 102 (in a RRC connectionreconfiguration message, for example). Accordingly, the SeNB may send306 the connection control message to the UE 102 via the PeNB.

Another example of generating a connection control message is given asfollows. A target SeNB may generate the connection control message. Inthis example, the target SeNB may send 306 the connection controlmessage to another eNB (e.g., a PeNB or a source SeNB). The other eNBmay then forward the connection control message to the UE 102.Accordingly, the target SeNB may send 306 the connection control messageto the UE 102 via another eNB.

FIG. 4 is a thread diagram illustrating one configuration of anon-contention based random access procedure 400. The eNB 460 may send401 a random access preamble assignment. For example, the eNB 460 mayassign the UE 402 a non-contention random access preamble (e.g., arandom access preamble that may not be within a set sent in broadcastsignaling). In some implementations, the eNB 460 may assign 401 therandom access preamble via a dedicated signaling in a downlink (via adedicated RACH preamble identity, for example).

The UE 402 may then send 403 the assigned non-contention random accesspreamble to the eNB 460. In some implementations, the UE 402 may send403 the assigned non-contention random access preamble on a RACH in anuplink transmission.

The eNB 460 may then send 405 a random access response to the UE 402.The random access response may be generated by MAC on DL-SCH. The UE 402may receive the random access response.

FIG. 5 is a thread diagram illustrating one configuration of acontention-based random access procedure 500. The UE 502 may select arandom access preamble. For example, the UE 502 may select a randomaccess preamble randomly from a set that may be informed in broadcastsignaling. The UE 502 may then send 501 the randomly selected randomaccess preamble to the eNB 560 (on a RACH in an uplink transmission, forexample).

The eNB 560 may send 503 a random access response. The UE 502 mayreceive the random access response. The random access response mayinclude a Temporary C-RNTI. The random access response may be generatedby MAC on DL-SCH.

The UE 502 may then send 505 a first scheduled uplink transmission onUL-SCH. In other words, the UE 502 may send 505 an uplink transmissionscheduled by the Temporary C-RNTI.

The eNB 560 may send 507 a contention resolution, which may be receivedby the UE 502. The contention resolution may include information thatconfirms that the UE 502 is identified.

FIG. 6 is a flow diagram illustrating another configuration of a method600 for establishing multiple radio connections by a UE 102. The UE 102may receive 602 a first PDCCH. The first PDCCH may include a first CRCthat may be scrambled by a first C-RNTI in a primary radio connection.As used herein, the term PDCCH may refer to a PDCCH or an EPDCCH. Forinstance, an EPDCCH may be one example of a PDCCH. The first PDCCH (orthe first EPDCCH) may include a first RNTI (e.g., a first C-RNTI) thatmay be implicitly coded with the first CRC. For example, a first set ofCRC parity bits may be scrambled by the first C-RNTI.

The UE 102 may then decode 604 the first PDCCH (or the first EPDCCH).Decoding 604 the first PDCCH may include interpreting the first PDCCH asdescribed in connection with FIG. 1. The first PDCCH may be transmittedfrom the eNB 160 to the UE 102 in a primary radio connection.

The UE 102 may receive 606 a second PDCCH. The second PDCCH may includea second CRC that may be scrambled by a second C-RNTI in a secondaryradio connection. The second PDCCH (or the second EPDCCH) may include asecond C-RNTI that may be implicitly coded with the second CRC. Forexample, a second set of CRC parity bits may be scrambled by the secondC-RNTI.

The UE 102 may then decode 608 the second PDCCH (or the second EPDCCH).Decoding 608 the second PDCCH may include interpreting the second PDCCHas described in connection with FIG. 1. The second PDCCH may betransmitted from the eNB 160 to the UE 102 in the secondary radioconnection.

FIG. 7 is a flow diagram illustrating another configuration of a method700 for establishing multiple radio connections by an eNB 160. The eNB160 may establish 702 a radio connection with the UE 102. In someimplementations, this may be performed as described in connection withFIG. 3.

The eNB 160 may manage a second C-RNTI for a secondary radio connection.For example, the eNB 160 may assign 704 a second C-RNTI for a secondradio connection to the UE 102 that has a first C-RNTI for a primaryradio connection. Assigning a C-RNTI to each radio connection may allowfor greater flexibility of radio resource management. In someimplementations, managing a second C-RNTI may include receiving theC-RNTI from another device (another eNB 160 (e.g., a SeNB) or a server,for example). For example, a PeNB may receive the second C-RNTI for asecondary radio connection from a SeNB that reserved the second C-RNTI.In this example, the eNB 160 may send the second C-RNTI to a UE 102. Itshould be noted that the second C-RNTI may be included in a connectioncontrol message included in a RRC connection reconfiguration messagefrom the eNB 160 to the UE 102.

In another example, managing a second C-RNTI may include generating thesecond C-RNTI. Generating the second C-RNTI may include reserving aC-RNTI. For example, a SeNB may reserve a C-RNTI for the secondary radioconnection. In this example, the SeNB may send the second C-RNTI toanother eNB (e.g., a PeNB or a source SeNB), for example. The eNB 160may then send the second C-RNTI to the UE 102. The second C-RNTI may beincluded in a connection control message included in a RRC connectionreconfiguration message from the eNB 160 to the UE 102.

The eNB 160 may transmit 706 a second PDCCH that includes a second CRCscrambled by the second C-RNTI in a secondary radio connection. Forexample, after the UE 102 is allocated the second C-RNTI by theconnection control message, the UE 102 has the second C-RNTI. After theUE 102 has the second C-RNTI for the secondary radio connection,transmitting 706 the second C-RNTI may include scrambling a set of CRCparity bits based on the second C-RNTI, as described above. In thisexample, the eNB 160 may transmit 706 the C-RNTI (and the correspondingCRC) in a PDCCH (or an EPDCCH). It should be noted that the eNB 160 maysend the C-RNTI to the UE 102 directly or indirectly (via another eNB,for example).

FIG. 8 is a block diagram illustrating one configuration of an E-UTRANarchitecture 823 in which systems and methods for establishing multipleradio connections may be implemented. The UE 802 described in connectionwith FIG. 8 may be implemented in accordance with the UE 102 describedin connection with FIG. 1. The eNB 860 described in connection with FIG.8 may be implemented in accordance with the eNB 160 described inconnection with FIG. 1. In the E-UTRAN architecture 823, the E-UTRAN 835may include one or more eNBs 860, providing the E-UTRA user plane(packet data convergence protocol (PDCP)/radio link control(RLC)/MAC/PHY) and control plane (RRC) protocol terminations toward theUE 802. The eNBs 860 may be interconnected with each other by an X2interface (not shown in the figure). The eNBs 860 may also be connectedby the S1 interfaces 831, 833 to the evolved packet core (EPC) 825. Forinstance, the eNBs 860 may be connected to a mobility management entity(MME) 827 by the S1-MME 831 interface and to the serving gateway (S-GW)829 by the S1-U interface 833. The S1 interfaces 831, 833 may support amany-to-many relation between MMEs 827, S-GWs 829 and the eNBs 860. TheS1-MME interface 831 may be the S1 interface for the control plane andthe S1-U interface 833 may be the S1 interface for the user plane. TheUu interface 837 may be a radio interface between the UE 802 and the eNB860 for the radio protocol of E-UTRAN 835.

The eNBs 860 may host a variety of functions. For example, the eNBs 860may host functions for radio resource management (e.g., radio bearercontrol, radio admission control, connection mobility control, dynamicallocation of resources to UEs 802 in both uplink and downlink(scheduling)). The eNBs 860 may also perform IP header compression andencryption of a user data stream, selection of an MME 827 at UE 802attachment when no routing to an MME 827 can be determined from theinformation provided by the UE 802 and routing of user plane datatowards the serving gateway 829. The eNBs 860 may additionally performscheduling and transmission of paging messages (originated from the MME827); scheduling and transmission of broadcast information (originatedfrom the MME 827 or operation and maintenance (O&M)); measurement andmeasurement reporting configuration for mobility and scheduling; andscheduling and transmission of the public warning system (PWS) (whichmay include the earthquake and tsunami warning system (ETWS) andcommercial mobile alert system (CMAS)) messages (originated from the MME827). The eNBs 860 may further perform closed subscriber group (CSG)handling and transport-level packet marking in the uplink.

The MME 827 may host a variety of functions. For example, the MME 827may perform Non-Access Stratum (NAS) signaling, NAS signaling security,access stratum (AS) security control, inter core network (CN) nodesignaling for mobility between 3GPP access networks, and idle mode UEReachability (including control and execution of paging retransmission).The MME 827 may also perform tracking area list management (for a UE 802in idle and active mode), packet data network gateway (PDN GW) and S-GWselection, MME 827 selection for handovers with MME 827 change andServing GPRS Support Node (SGSN) selection for handovers to 2G or 3G3GPP access networks. The MME 827 may additionally host roaming,authentication and bearer management functions (including dedicatedbearer establishment). The MME 827 may provide support for PWS (whichincludes ETWS and CMAS) message transmission, and may optionally performpaging optimization.

The S-GW 829 may also host the following functions. The S-GW 829 mayhost the local mobility anchor point for inter-eNB 860 handover. TheS-GW 829 may perform mobility anchoring for inter-3GPP mobility, E-UTRANidle mode downlink packet buffering and initiation of network triggeredservice request procedure, lawful interception and packet routing andforwarding. The S-GW 829 may also perform transport-level packet markingin the uplink and the downlink, accounting on user and QoS ClassIdentifier (QCI) granularity for inter-operator charging, and UL and DLcharging per UE 802, packet data network (PDN) and QCI.

Signaling Radio Bearers (SRBs) are Radio Bearers (RB) that may be usedonly for the transmission of RRC and NAS messages. Three SRBs aredefined. SRB0 may be used for RRC messages using the CCCH logicalchannel. SRB1 may be used for RRC messages (which may include apiggybacked NAS message) as well as for NAS messages prior to theestablishment of SRB2, all using the DCCH logical channel. SRB2 may beused for RRC messages, which include logged measurement information aswell as for NAS messages, all using the DCCH logical channel. SRB2 has alower priority than SRB1 and may be configured by the E-UTRAN 835 aftersecurity activation.

RRC connection establishment may involve the establishment of SRB1. Uponinitiating the initial security activation procedure, the E-UTRAN 835may initiate the establishment of SRB2 and DRBs. The E-UTRAN 835 may dothis prior to receiving the confirmation of the initial securityactivation from the UE 802. PDCP may be established for each SRB1, SRB2and DRB. RLC may be established for each SRB0, SRB1, SRB2 and DRB.

RRC may be responsible for the establishment, maintenance and release ofan RRC connection between the UE 802 and the E-UTRAN 835, includingallocation of temporary identifiers between the UE 802 and the E-UTRAN835 and configuration of SRBs for RRC connection, etc. RRC may beresponsible for the establishment, configuration, maintenance andrelease of point-to-point RBs.

FIG. 9 is a block diagram illustrating one configuration of a user planeprotocol stack. The UE 902 described in connection with FIG. 9 may beimplemented in accordance with the UE 102 described in connection withFIG. 1. The eNB 960 described in connection with FIG. 9 may beimplemented in accordance with the eNB 160 described in connection withFIG. 1. The user plane protocol stack for the UE 902 may include PDCP939 a, RLC 941 a, MAC 943 a and PHY 945 a sublayers. The user planeprotocol stack for the eNB 960 may include corresponding PDCP 939 b, RLC941 b, MAC 943 b and PHY 945 b sublayers. The PDCP 939 b, RLC 941 b, MAC943 b and PHY 945 b sublayers (which terminate at the eNB 960 on thenetwork) may perform functions (e.g., header compression, ciphering,scheduling, Automatic Repeat Request (ARQ) and Hybrid Automatic RepeatRequest (HARQ)) for the user plane. Different entities may be identifiedby the corresponding sublayer. For example, PDCP entities are located inthe PDCP 939 sublayer, RLC entities are located in the RLC sublayer 941,MAC entities are located in the MAC sublayer 943 and PHY entities arelocated in the PHY sublayer 945.

It should be noted that in multi-connectivity, the UE 902 may have morethan one PHY entity and more than one MAC entity. One radio connection(e.g., radio interface) may include one PHY entity and one MAC entity.For example, a primary radio connection may include one PHY entity andone MAC entity and a secondary radio connection may include one PHYentity and one MAC entity. To enable flexibility of radio resourcemanagement for each network node, a distinct C-RNTI may be assigned foreach radio connection.

FIG. 10 is a block diagram illustrating one configuration of a controlplane protocol stack. The UE 1002 described in connection with FIG. 10may be implemented in accordance with the UE 102 described in connectionwith FIG. 1. The eNB 1060 described in connection with FIG. 10 may beimplemented in accordance with the eNB 160 described in connection withFIG. 1. The MME 1027 described in connection with FIG. 10 may beimplemented in accordance with the MME 827 described in connection withFIG. 8.

The control plane protocol stack for the UE 1002 may include PDCP 1039a, RLC 1041 a, MAC 1043 a and PHY 1045 a sublayers. The UE 1002 may alsoinclude a NAS 1047 a and a RRC 1049 a sublayer. The control planeprotocol stack for the eNB 1060 may include RRC 1049 b, PDCP 1039 b, RLC1041 b, MAC 1043 b and PHY 1045 b sublayers. The MME 1027 may include aNAS 1047 b sublayer. The PDCP 1039 b sublayer (terminated in eNB 1060 onthe network side) may perform functions (e.g., ciphering and integrityprotection) for the control plane. The RLC 1041 b and MAC 1043 bsublayers (terminated in eNB 1060 on the network side) may perform thesame functions as for the user plane.

The RRC 1049 b sublayer (terminated in eNB 1060 on the network side) mayperform the following functions. The RRC 1049 b sublayer may performbroadcast functions, paging, RRC 1049 connection management, radiobearer (RB) control, mobility functions, UE 1002 measurement reportingand control. The NAS 1047 control protocol (terminated in MME 1027 onthe network side) may perform, among other things, evolved packet system(EPS) bearer management, authentication, evolved packet systemconnection management (ECM)-IDLE mobility handling, paging originationin ECM-IDLE and security control.

FIG. 11 is a block diagram illustrating a carrier aggregationconfiguration in which a first cell 1153 and a second cell 1155 areco-located, overlaid and have approximately equal coverage. Intraditional carrier aggregation, two or more component carriers (CCs)may be aggregated to support wider transmission bandwidths (e.g., up to100 MHz). A UE 102 may simultaneously receive or transmit on one ormultiple CCs depending on the capabilities of the UE 102. For example,according to Rel-10 and later, a UE 102 with reception and/ortransmission capabilities for carrier aggregation may simultaneouslyreceive and/or transmit on multiple CCs corresponding to multipleserving cells. According to Rel-8 and Rel-9, a UE 102 may receive on asingle CC and transmit on a single CC corresponding to one serving cell.

When carrier aggregation is configured, the UE 102 may have one RRCconnection with the network. One radio interface may provide carrieraggregation. During RRC connection establishment, re-establishment andhandover, one serving cell may provide NAS mobility information (e.g., atracking area identity (TAI)). During RRC connection re-establishmentand handover, one serving cell may provide a security input. This cellmay be referred to as the primary cell (PCell). In the downlink, thecomponent carrier corresponding to the PCell may be the downlink primarycomponent carrier (DL PCC), while in the uplink it may be the uplinkprimary component carrier (UL PCC).

Depending on UE 102 capabilities, one or more SCells may be configuredto form together with the PCell a set of serving cells. In the downlink,the component carrier corresponding to a SCell may be a downlinksecondary component carrier (DL SCC), while in the uplink it may be anuplink secondary component carrier (UL SCC).

The configured set of serving cells for the UE 102, therefore, mayconsist of one PCell and one or more SCells. For each SCell, the usageof uplink resources by the UE 102 (in addition to the downlinkresources) may be configurable. The number of DL SCCs configured may belarger than or equal to the number of UL SCCs and no SCell may beconfigured for usage of uplink resources only.

From a UE 102 viewpoint, each uplink resource may belong to one servingcell. The number of serving cells that may be configured depends on theaggregation capability of the UE 102. The PCell may only be changedusing a handover procedure (e.g., with a security key change and a RACHprocedure). The PCell may be used for transmission of the PUCCH. Unlikethe SCells, the PCell may not be de-activated. Re-establishment may betriggered when the PCell experiences radio link failure (RLF), not whenthe SCells experience RLF. Furthermore, NAS information may be takenfrom the PCell.

The reconfiguration, addition and removal of SCells may be performed byRRC. At intra-LTE handover, RRC may also add, remove or reconfigureSCells for usage with a target PCell. When adding a new SCell, dedicatedRRC signaling may be used for sending all required system information ofthe SCell (e.g., while in connected mode, UEs 102 need not acquirebroadcasted system information directly from the SCells).

As illustrated in FIG. 11, one carrier aggregation deploymentconfiguration may include frequency 1 (F1) cells 1153 and frequency 2(F2) cells 1155 that are co-located and overlaid. It should be notedthat carrier aggregation scenarios (e.g., deployment configurations) maybe independent of small cell scenarios. The eNBs 1160 a-c described inconnection with FIG. 11 may be implemented in accordance with the eNB160 described in connection with FIG. 1. In this configuration, multipleeNBs 1160 a-c may provide coverage for the F1 cells 1153 and the F2cells 1155. The systems and methods disclosed herein may be used toestablish radio interfaces between the F1 cells 1153 and the F2 cells1155.

The coverage of the F1 cells 1153 and the F2 cells 1155 may be the sameor nearly the same. Both layers (e.g., frequency layers) may providesufficient coverage and mobility may be supported on both layers. Alikely scenario for this configuration may be when the F1 cells 1153 andthe F2 cells 1155 are of the same band (e.g., 2 gigahertz (GHz), 800MHz, etc.). It is expected that carrier aggregation may be possiblebetween the overlaid F1 cells 1153 and the F2 cells 1155.

FIG. 12 is a block diagram illustrating a carrier aggregationconfiguration in which a first cell 1253 and a second cell 1255 areco-located and overlaid, but the second cell 1255 has smaller coverage.The eNBs 1260 a-c described in connection with FIG. 12 may beimplemented in accordance with the eNB 160 described in connection withFIG. 1. In this configuration, multiple eNBs 1260 a-c may providecoverage for the F1 cells 1253 and the F2 cells 1255. The systems andmethods disclosed herein may be used to establish radio interfacesbetween the F1 cells 1253 and the F2 cells 1255.

In this configuration, the F1 cells 1253 and the F2 cells 1255 may beco-located and overlaid, but the F2 cells 1255 may have smaller coveragedue to larger path loss. Only the F1 cells 1253 may provide sufficientcoverage and the F2 cells 1255 may be used to improve throughput.Mobility may be performed based on F1 cell 1253 coverage. A likelyscenario for this configuration may be when the F1 cells 1253 and the F2cells 1255 are of different bands. For example, the F1 cells 1253 mayequal 800 MHz or 2 GHz and the F2 cells 1255 may equal 3.5 GHz, etc. Itis expected that carrier aggregation may be possible between theoverlaid F1 cells 1253 and the F2 cells 1255.

FIG. 13 is a block diagram illustrating a carrier aggregationconfiguration in which a first cell 1353 and second cell 1355 areco-located, but the second cell 1355 antennas are directed to the cellboundaries of the first cell 1353. The eNBs 1360 a-c described inconnection with FIG. 13 may be implemented in accordance with the eNB160 described in connection with FIG. 1. The systems and methodsdisclosed herein may be used to establish radio interfaces between theF1 cells 1353 and F2 cells 1355.

In this configuration, the F1 cells 1353 and the F2 cells 1355 may beco-located, but the F2 cell 1355 antennas may be directed to the cellboundaries of the F1 cell 1353 so that cell edge throughput may beincreased. The F1 cell 1353 may provide sufficient coverage, but the F2cell 1353 may potentially have holes (e.g., due to larger path loss).Mobility may be based on F1 cell 1353 coverage. A likely scenario forthis configuration may be when the F1 cell 1353 and the F2 cell 1355 areof different bands. For example, the F1 cell 1353 may equal 800 MHz or 2GHz and the F2 cell 1355 may equal 3.5 GHz, etc. It is expected that theF1 cell 1353 and the F2 cell 1355 of the same eNB 1360 may be aggregatedwhere coverage overlaps.

FIG. 14 is a block diagram illustrating a carrier aggregationconfiguration in which a first cell 1453 provides macro coverage and inwhich remote radio heads (RRH) 1457 a-j on the second cell 1455 are usedto improve throughput at hotspots. The eNBs 1460 a-c described inconnection with FIG. 14 may be implemented in accordance with the eNB160 described in connection with FIG. 1. In this configuration, multipleeNBs 1460 a-c may provide macro coverage for a first cell 1453. RRHs1457 a-j may be connected to the eNBs 1460 a-c and may provide secondcell 1455 coverage. The systems and methods disclosed herein may be usedto establish radio interfaces between the F1 cells 1453 and F2 cells1455.

In this configuration, the F1 cells 1453 may provide macro coverage andthe remote radio heads (RRH) 1457 a-j on F2 cells 1455 may be used toimprove throughput at hotspots. Mobility may be performed based on F1cell 1453 coverage. A likely scenario for this configuration may be whenF1 cells 1453 and F2 cells 1455 are of different bands. For example, theF1 cell 1453 may equal 900 MHz or 2 GHz and the F2 cell 1455 may equal3.5 GHz, etc. It is expected that the F2 RRH cells 1455 may beaggregated with the underlying F1 cell 1453 (e.g., the macro cells).

FIG. 15 is a block diagram illustrating a carrier aggregationconfiguration in which frequency selective repeaters 1559 a-c aredeployed. This configuration may be similar to the configurationdescribed in connection with FIG. 10. The systems and methods disclosedherein may be used to establish radio interfaces between the F1 cells1553 and the F2 cells 1555. In this configuration, frequency selectiverepeaters 1559 a-c may be deployed so that coverage may be extended forone of the carrier frequencies. The eNBs 1560 a-c described inconnection with FIG. 15 may be implemented in accordance with the eNB160 described in connection with FIG. 1. Multiple eNBs 1560 a-c may beassociated with the F1 cells 1553. It is expected that an F1 cell 1553and an F2 cell 1555 may be aggregated where coverage overlaps.

FIG. 16 is a block diagram illustrating multiple coverage scenarios 1661a-d for small cells with and without macro coverage. The eNBs 1660 a-kdescribed in connection with FIG. 16 may be implemented in accordancewith the eNB 160 described in connection with FIG. 1. The coveragescenarios 1661 a-d may include indoor and outdoor scenarios usinglow-power nodes (e.g., eNBs 1660 b-k). These low-power nodes may providesmall cell coverage (e.g., F2 coverage 1655). An eNB 1660 a may providemacro cell coverage (e.g., F1 coverage 1653).

Small cell enhancements may target both scenarios in which macrocoverage may or may not be present. The systems and methods describedherein may provide for establishing multiple connections in small celldeployment scenarios. These scenarios may include both outdoor andindoor small cell deployments and both ideal and non-ideal backhaul.Additionally, multiple connections may be established in both sparse anddense small cell deployments.

The E-UTRAN architecture may be able to achieve the system and mobilityperformance for small cell enhancement. For example, before the type ofinterface (connection) is determined, the E-UTRAN architecture mayidentify which kind of information may be needed (or may be beneficial)to be exchanged between nodes in order to get the desired improvements.In some implementations, the systems and methods described herein mayidentify potential technologies in the protocol and architecture thatmay provide enhanced support of small cell deployment and operation. Insome configurations, these potential technologies may be implemented inaccordance with scenarios and requirements as described in TR 36.932.

For example, the systems and methods described herein may identify andevaluate the benefits of UEs 102 having multi-connectivity to macro andsmall cell layers that may be served by different (or the same)carrier(s). The systems and methods described herein may also identifyand evaluate scenarios where multi-connectivity may be feasible andbeneficial.

The systems and methods described herein may identify and evaluatepotential architectures and protocol enhancements for differentscenarios (such as those described in TR 36.392). The differentscenarios may include a scenario that implements multi-connectivity andthat minimizes core network impacts. For example, the systems andmethods described herein may provide the overall structure of a controlplane and a user plane and their relation to each other. For example,the control plane and the user plane may be supported in differentnodes, termination of different protocol layers, etc.

In a small cell deployment scenario, each node (e.g., eNB 1660 a-k) mayhave its own independent scheduler. To utilize radio resourcesefficiently, a UE 102 may connect to multiple nodes that have differentschedulers. To connect to multiple nodes that have different schedulers,multiple connections between the UE 102 and E-UTRAN 435 may beestablished.

The first coverage scenario 1661 a illustrates a single small cell(e.g., the F2) with macro coverage (e.g., the F1). In FIG. 16, F1 may bethe carrier frequency for the macro layer, and F2 may be the carrierfrequency of the local-node layer. In the first coverage scenario 1661a, the macro cell may overlap the small cell.

The second coverage scenario 1661 b illustrates a single small cellwithout macro coverage. The third coverage scenario 1661 c illustratesmultiple small cells with overlapping macro cell coverage. The fourthcoverage scenario 1661 d illustrates multiple small cells without macrocell coverage.

FIG. 17 is a block diagram illustrating one configuration of an E-UTRAN1735 and a UE 1702 in which systems and methods for establishingmultiple radio connections may be implemented. The UE 1702 and theE-UTRAN 1735 described in connection with FIG. 17 may be implemented inaccordance with corresponding elements described in connection with atleast one of FIGS. 1 and 6.

FIG. 17 depicts one C-RNTI 1765 a-b per radio connection 1769 a-b. Usingone C-RNTI 1765 a-b per radio connection 1769 a-b may maintainflexibility in radio resource management. For example, a first C-RNTI1765 a may be allocated to the primary radio connection 1769 a. A secondC-RNTI 1765 b may be allocated to the secondary radio connection 1769 b.In some implementations, the first C-RNTI 1765 a may be allocated inaccordance with Rel-11. For example, the first C-RNTI 1765 a may beassigned after a random access. In some cases, a random access mayinclude initial access when the UE 1702 is in an RRC_IDLE state or whenthe UE 1702 has completed a RRC connection re-establishment procedure.In another example, the first C-RNTI 1765 a may be updated during ahandover procedure.

The second C-RNTI 1765 b (for the secondary radio connection 1769 b) maybe allocated by control signaling (e.g., RRC dedicated signaling) fromthe E-UTRAN 1735 (e.g., the PeNB 1760 a or the SeNB 1760 b) to the UE1702. The usage of the first C-RNTI 1765 a and the second C-RNTI 1765 bmay be in accordance with the usages described in connection with Table(2).

In some implementations, a C-RNTI 1765 may be unique for a cell. Forexample, for a certain cell, a value for a first C-RNTI 1765 a (or asecond C-RNTI 1765 b) may be used for the UE 1702. In this example, thevalue should not be used for another C-RNTI 1765 in the cell. TheE-UTRAN 1735 may manage the allocation of a first C-RNTI 1765 a and/or asecond C-RNTI 1765 b for each UE 1702 such that the C-RNTI values do notconflict with each other. Also, it should be noted that if the UE 1702is configured with multiple serving cells in a radio connection 1769,the same C-RNTI 1765 may be allocated to the serving cells for eachradio connection 1769.

In some implementations, the E-UTRAN 1735 may include a PeNB 1760 a anda SeNB 1760 b. The UE 1702 may communicate with the PeNB 1760 a via theprimary radio connection 1769 a. The UE 1702 may communicate with theSeNB 1760 b via the secondary radio connection 1769 b. While FIG. 17depicts one primary radio connection 1769 a and one secondary radioconnection 1769 b, the UE 1702 may be configured with one primary radioconnection 1769 a and one or more secondary radio connections 1769 b.The PeNB 1760 a and SeNB 1760 b may be implemented in accordance withthe eNB 160 described in connection with FIG. 1.

The PeNB 1760 a may provide multiple cells 1767 a-c for connection toone or more UEs 1702. For example, the PeNB 1760 a may provide cell A1767 a, cell B 1767 b and cell C 1767 c. Similarly, the SeNB 1760 b mayprovide multiple cells 1767 d-f. The UE 1702 may be configured totransmit/receive on one or more cells (e.g., cell A 1767 a, cell B 1767b and cell C 1767 c) for the primary radio connection 1769 a (e.g., aprimary Uu interface). The UE 1702 may also be configured totransmit/receive on one or more other cells (e.g., cell D 1767 d, cell E1767 e and cell F 1767 f) for the secondary radio connection 1769 b(e.g., a secondary Uu interface). If the UE 1702 is configured totransmit/receive on multiple cells 1767 a-f for a radio connection 1769a-b, a carrier aggregation operation may be applied to the radioconnection 1769 a-b. In some implementations, another UE 1702 may beconfigured with cell A 1767 a for the secondary radio connection 1769 band cell D 1767 d for a primary radio connection 1769 a. In thisimplementation, mapping cells to a radio connection 1769 may be a UE1702 specific configuration.

As described above, one MAC entity 1771 a-b and one PHY entity 1773 a-bmay be mapped to one radio connection 1769 a-b. For example, a first MACentity 1771 a and a first PHY entity 1773 a may be mapped to the primaryradio connection 1769 a. Similarly, a second MAC entity 1771 b and asecond PHY entity 1773 b may be mapped to the secondary radio connection1769 b.

In some implementations, the PeNB 1760 a may manage and store at leastone C-RNTI 1765 for each UE 1702 using the configured cells 1767 a-c.For example, the PeNB 1760 a may manage and store multiple first C-RNTIs1765 a corresponding to UEs 1702 that have a primary radio connection1769 a with the PeNB 1760 a. In a similar fashion, the SeNB 1760 b maymanage and store at least one C-RNTI 1765 b for the secondary radioconnection(s) 1769 b for each UE 1702 using the configured cells 1767d-f. For example, the SeNB 1760 b may manage and store multiple secondC-RNTIs 1765 b corresponding to UEs 1702 that have a secondary radioconnection 1769 b with the SeNB 1760 b.

In some implementations, the PeNB 1760 a may also store and managemultiple second C-RNTIs 1765 b corresponding to UEs 1702 that have asecondary radio connection with the PeNB 1760 a. For UEs that have asecondary radio connection with the eNB 1760 a, the eNB 1760 a should(instead) be considered a SeNB. In this implementation, an eNB maybehave as both the PeNB 1760 a and the SeNB 1760 b.

In some implementations, the MAC entities 1771 a-b may have an interfacewith an RRC entity 1775. In this implementation, the RRC entity 1775 mayprovide the first C-RNTI 1765 a to the first MAC entity 1771 a and thesecond C-RNTI 1765 b to the second MAC entity 1771 b. The RRC entity1775 may receive RRC messages (e.g., RRC connection reconfigurationmessage, connection control message, handover command, etc.) from a RRCentity (not shown) of the E-UTRAN 1735. The RRC entity 1775 may alsotransmit RRC messages (e.g. RRC connection reconfiguration completemessage) to the RRC entity (not shown) of the E-UTRAN 1735. The RRCentity 1775 may also store the first C-RNTI 1765 a and the second C-RNTI1765 b. The MAC entities 1771 a-b may control the decoding of the PDCCH(or the EPDCCH) based on the C-RNTIs 1765.

FIG. 18 is a thread diagram 1800 illustrating one configuration of eNBs1860 a-b and a UE 1802 in which systems and methods for establishingmultiple radio connections may be implemented. Specifically, FIG. 18illustrates one example of procedures for adding a radio connection. TheeNBs 1860 a-b and the UE 1802 described in connection with FIG. 18 maybe implemented in accordance with one or more corresponding elementsdescribed in connection with FIG. 1.

The PeNB 1860 a may configure UE 1802 measurement procedures via layer 3(L3) signaling (e.g., an RRC message). The UE 1802 measurementprocedures may be based on area restriction information. Themeasurements provided by the PeNB 1860 a may assist in controlling theUE's 1802 connection mobility. The PeNB 1860 a may then send 1877 ameasurement control to the UE 1802. The PeNB 1860 a may send 1879 anuplink allocation to the UE 1802 via layer 1 (L1)/layer 2 (L2) signaling(e.g., PDCCH, a MAC control element).

The measurement control may trigger the UE 1802 to send 1881 ameasurement report to the PeNB 1860 a. The UE 1802 may be triggered tosend 1881 the measurement report based on one or more rules (e.g.,system information, a specification, etc.). Based on the measurementreport and other information, the PeNB 1860 a may decide 1883 to addanother connection to the UE 1802. An example of other information mayinclude radio resource management information.

The PeNB 1860 a may then issue 1885 a connection request message to theSeNB 1860 b. The connection request message may be based on themeasurement report and radio resource management information. Theconnection request message may include necessary information that allowsthe SeNB 1860 b to prepare the addition of connection. For example, theconnection request message may include RRC context including the C-RNTIof the UE 1802 in the PeNB, QoS information, etc. One or more of UE X2and UE S1 signaling references may enable the SeNB 1860 b to address thePeNB 1860 a and the evolved packet core (EPC).

The SeNB 1860 b may perform 1887 admission control. In someimplementations, the admission control may be based on the received QoSinformation. The admission control may evaluate whether a required QoSmay be achieved if the resources can be granted by the SeNB 1860 b, inorder to increase the likelihood of a successful connection control. Insome implementations, the SeNB 1860 b may configure resources accordingto the received QoS information. The SeNB 1860 may also reserve one ormore of a C-RNTI, a cell and optionally, a RACH preamble identity.

The SeNB 1860 b may prepare the addition of connection with one or moreof L1 (PHY) and L2 (MAC) entities of the SeNB 1660 b and may send 1889 aconnection request acknowledge (Ack) to the PeNB 1860 a. The connectionrequest Ack may include a transparent container to be sent to the UE1802 (from the PeNB 1860 a, for example) as a connection control message(in an RRC connection reconfiguration message, for example) that directsthe UE 1802 to perform an addition of connection. The container mayinclude a new C-RNTI (e.g., a second C-RNTI), a physical cell identifierfor a cell to be accessed (e.g., a target cell) in a secondary radioconnection, SeNB 1860 b security algorithm identifiers for the selectedsecurity algorithms and a dedicated RACH preamble identity. Theconnection control message may also include other parameters (e.g., aradio bearer configuration, access parameters, SIBs, etc.) Specifically,the connection control message may indicate whether a dedicated RACHpreamble identity is included or not.

The PeNB 1860 a may generate the RRC connection reconfiguration messagethat includes instructions to perform the addition of connection (e.g.,the RRCConnectionReconfiguration message including connection controlmessage) to be sent to the UE 1802. To schedule 1893 the connectioncontrol message (abbreviated as “RRC Conn. Reconf.” in FIG. 18 forconvenience), the PeNB 1860 a may send 1891 a downlink allocation to theUE 1802 via L1/L2 signaling.

The UE 1802 may receive the RRC connection reconfiguration messageincluding the connection control message (e.g., theRRCConnectionReconfiguration message with the necessary parameters(C-RNTI for the secondary radio connection, SeNB 1860 b securityalgorithm identifiers, and optionally a dedicated RACH preambleidentity, SeNB 1860 b SIBs, etc.)). The PeNB 1860 a may then command ordirect the UE 1802 to perform the addition of connection.

After receiving the connection control message (e.g., the connectioncontrol message included in the RRCConnectionReconfiguration message),the UE 1802 may synchronize 1895 (e.g., acquire synchronization signals)with the SeNB 1860 b and may access (e.g., perform a random accessprocedure) the target cell via the RACH. The UE 1802 may access thetarget cell following a contention-free random access procedure (e.g.,non-contention-based random access procedure) if a dedicated RACHpreamble was indicated in the connection control information (adedicated RACH preamble identity was included in the connection controlmessage, for example). By comparison, the UE 1802 may access the targetcell following a contention-based random access procedure if nodedicated preamble was indicated. In some implementations, the UE 1802may derive SeNB 1860 b specific keys and may configure the selectedsecurity algorithms to be used in the target cell.

In some implementations, the SeNB 1860 b may respond to the randomaccess by sending 1897 an uplink allocation and a timing advance to theUE 1802. Then, when the UE 1802 has successfully accessed the targetcell, the UE 1802 may send 1899 a RRC connection reconfigurationcomplete message (e.g., the RRCConnectionReconfigurationCompletemessage), which may include the second C-RNTI, to confirm the additionof the connection. The UE 1802 may also send an uplink buffer statusreport to the SeNB 1860 b to indicate that the connection additionprocedure has been completed for the UE 1802. The SeNB 1860 b may verifythe second C-RNTI sent in the RRC connection reconfiguration completemessage (e.g., the RRCConnectionReconfigurationComplete message). TheSeNB 1860 b may then begin sending data to the UE 1802.

It should be noted that different levels of signaling may be used fordifferent steps of the method. For example, one or more of sending 1877a measurement control, sending 1881 a measurement report, sending 1885 aconnection request, sending 1889 a connection request acknowledge,sending 1893 a connection control message, and sending 1899 a RRCconnection reconfiguration complete message may be performed using L3signaling. By comparison, one or more of sending 1879 an uplinkallocation, sending 1891 a downlink allocation, synchronizing 1895 andsending 1897 an uplink allocation and timing advance may be performedusing one or more of L1 and L2 signaling.

FIG. 19 is a thread diagram 1900 illustrating one configuration of eNBs1960 a-b and a UE 1902 in which systems and methods for establishingmultiple radio connections may be implemented. Specifically, FIG. 19illustrates an example of procedures for changing a cell in a radioconnection (e.g., handover in the secondary radio connection). In thisexample, information exchange between the PeNB and a source SeNB isomitted. The eNBs 1960 a-b and the UE 1902 described in connection withFIG. 19 may be implemented in accordance with one or more correspondingelements described in connection with FIG. 1.

The eNB 1960 a (e.g., a PeNB or a source SeNB) may configure UE 1902measurement procedures. The UE 1902 measurement procedures may be basedon area restriction information. The measurements provided by the eNB1960 a may assist in controlling the UE's 1902 connection mobility. TheeNB 1960 a may then send 1977 a measurement control to the UE 1902. TheeNB 1960 a may send 1979 an uplink allocation to the UE 1902 via L1/L2signaling (e.g., PDCCH, a MAC control element).

The measurement control may trigger the UE 1902 to send 1981 ameasurement report to the eNB 1960 a. The UE 1902 may be triggered tosend 1981 the measurement report based on one or more rules (e.g.,system information, a specification, etc.). Based on the measurementreport and other information, the eNB 1960 a may decide 1983 to change acell to the UE 1902. An example of other information may include radioresource management information.

The eNB 1960 a may then issue 1985 a connection request message to thetarget SeNB 1660 b. The connection request message may be based on themeasurement report and radio resource management information. Theconnection request message may include necessary information that allowsthe target SeNB 1960 b to prepare the handover in the secondaryconnection. For example, the connection request message may include RRCcontext including the C-RNTI of the UE 1902 in the source eNB, QoSinformation, etc. One or more of the UE X2 and UE S1 signalingreferences may enable the target SeNB 1960 b to address the eNB 1960 aand the EPC.

The target SeNB 1960 b may perform 1987 admission control. In someimplementations, the admission control may be based on the received QoSinformation. The admission control may evaluate whether the required QoSmay be achieved if the resources can be granted by the target SeNB 1760b, in order to increase the likelihood of a successful connectioncontrol. In some implementations, the target SeNB 1960 b may configureresources according to the received QoS information. The target SeNB1960 b may also reserve at least one of a C-RNTI, a cell and optionally,a RACH preamble identity.

The target SeNB 1960 b may prepare the handover in the secondaryconnection with one or more of L1 (PHY) and L2 (MAC) entities of the eNB1760 a and may send 1989 a connection request Ack to the eNB 1960 a. Theconnection request Ack may include a transparent container to be sent tothe UE 1902 (from the eNB 1960 a, for example) as a connection controlmessage (in an RRC connection reconfiguration message, for example) thatdirects the UE 1902 to perform the handover in the secondary connection.The container may include a new C-RNTI (e.g., a second C-RNTI), aphysical cell identifier for a cell to be accessed (e.g., a target cell)in a secondary radio connection, target SeNB 1960 b security algorithmidentifiers for the selected security algorithms and a dedicated RACHpreamble identity. The connection control message may also include otherparameters (e.g., access parameters, system information blocks (SIBs),etc.) Specifically, the connection control message may indicate whethera dedicated RACH preamble identity has been included or not.

The eNB 1960 a may generate the RRC connection reconfiguration messageto perform the handover (e.g., the RRCConnectionReconfiguration messageincluding connection control information) to be sent to the UE 1902. Toschedule 1993 the connection control message (abbreviated as “RRC Conn.Reconf.” in FIG. 19 for convenience), the eNB 1960 a may send 1991 adownlink allocation to the UE 1902.

The UE 1902 may receive the RRC connection reconfiguration messageincluding the connection control message (e.g., theRRCConnectionReconfiguration message with necessary parameters (C-RNTIfor the secondary radio connection, target SeNB 1960 b securityalgorithm identifiers, and optionally dedicated RACH preamble identity,target SeNB 1960 b SIBs, etc.)). The eNB 1960 a may then command ordirect the UE 1902 to perform the handover in the secondary connection.

After receiving the connection control message (e.g., the connectioncontrol message included in the RRCConnectionReconfiguration message),the UE 1902 may synchronize 1995 (e.g., acquire synchronization signals)with the target SeNB 1960 b and may access (e.g., perform a randomaccess procedure) the target cell via the RACH. The UE 1902 may accessthe target cell following a contention-free random access procedure(e.g., non-contention-based random access procedure) if a dedicated RACHpreamble was indicated in the connection control information (adedicated RACH preamble identity was included in the connection controlmessage, for example). By comparison, the UE 1902 may access the targetcell following a contention-based random access procedure if nodedicated preamble was indicated. In some implementations, the UE 1902may derive target SeNB 1960 b specific keys and may configure theselected security algorithms to be used in the target cell.

In some implementations, the target SeNB 1960 b may respond to therandom access by sending 1997 an uplink allocation and a timing advanceto the UE 1902. Then, when the UE 1902 has successfully accessed thetarget cell, the UE 1902 may send 1999 a RRC connection reconfigurationcomplete message (e.g., the RRCConnectionReconfigurationCompletemessage), which may include the second C-RNTI, to confirm the additionof the connection. The UE 1902 may also send an uplink buffer statusreport to the target SeNB 1960 b to indicate that the connectionaddition procedure has been completed for the UE 1902. The target SeNB1960 b may verify the second C-RNTI sent in the RRC connectionreconfiguration complete message (e.g., theRRCConnectionReconfigurationComplete message). The target SeNB 1960 bmay then begin sending data to the UE 1902.

It should be noted that different levels of signaling may be used fordifferent steps of the method. For example, one or more of sending 1977a measurement control, sending 1981 a measurement report, sending 1985 aconnection request, sending 1989 a connection request acknowledgemessage, sending 1993 a connection control message, and sending 1999 aRRC connection reconfiguration complete message may be performed usingL3 signaling. By comparison, one or more of sending 1979 an uplinkallocation, sending 1991 a downlink allocation, synchronizing 1995 andsending 1997 an uplink allocation and timing advance may be performedusing one or more of L1 and L2 signaling.

It should be noted that in FIGS. 18 and 19, similar connection controlinformation may be used. This connection control information may have asimilar structure as mobility control information used for handover fora single connection. This connection control information may also beused for intra-SeNB handover (e.g., cell change in a SeNB) andself-handover (e.g., handover to the same cell).

In FIG. 19, instead of a connection control message, a handover command(i.e., MobilityControlInfo) may be used. The handover command in thesecondary radio connection may be included in a secondary RRC connectionreconfiguration message which is distinguished from the RRC connectionreconfiguration message used in the primary radio connection. After thesecondary radio connection is added, the secondary RRC connectionreconfiguration message is used to configure/reconfigure parameters ofthe secondary radio connection. Then, a secondary RRC connectionreconfiguration complete message may be sent from the UE 102 to thetarget SeNB as an acknowledgement to the secondary RRC connectionreconfiguration message. The secondary RRC connection reconfigurationcomplete message may be distinguished from the RRC connectionreconfiguration complete message used in the primary radio connection.

FIG. 20 illustrates various components that may be utilized in a UE2002. The UE 2002 described in connection with FIG. 20 may beimplemented in accordance with the UE 102 described in connection withFIG. 1. The UE 2002 includes a processor 2004 that controls operation ofthe UE 2002. The processor 2004 may also be referred to as a centralprocessing unit (CPU). Memory 2010, which may include read-only memory(ROM), random access memory (RAM), a combination of the two or any typeof device that may store information, provides instructions 2006 a anddata 2008 a to the processor 2004. A portion of the memory 2010 may alsoinclude non-volatile random access memory (NVRAM). Instructions 2006 band data 2008 b may also reside in the processor 2004. Instructions 2006b and/or data 2008 b loaded into the processor 2004 may also includeinstructions 2006 a and/or data 2008 a from memory 2010 that were loadedfor execution or processing by the processor 2004. The instructions 2006b may be executed by the processor 2004 to implement one or more of themethods and procedures 200, 600, 1800 and 1900 described above.

The UE 2002 may also include a housing that contains one or moretransmitters 2058 and one or more receivers 2020 to allow transmissionand reception of data. The transmitter(s) 2058 and receiver(s) 2020 maybe combined into one or more transceivers 2018. One or more antennas2022 a-n are attached to the housing and electrically coupled to thetransceiver 2018.

The various components of the UE 2002 are coupled together by a bussystem 2014, which may include a power bus, a control signal bus and astatus signal bus, in addition to a data bus. However, for the sake ofclarity, the various buses are illustrated in FIG. 20 as the bus system2014. The UE 2002 may also include a digital signal processor (DSP) 2012for use in processing signals. The UE 2002 may also include acommunications interface 2016 that provides user access to the functionsof the UE 2002. The UE 2002 illustrated in FIG. 20 is a functional blockdiagram rather than a listing of specific components.

FIG. 21 illustrates various components that may be utilized in an eNB2160. The eNB 2160 described in connection with FIG. 21 may beimplemented in accordance with the eNB 160 described in connection withFIG. 1. The eNB 2160 includes a processor 2104 that controls operationof the eNB 2160. The processor 2104 may also be referred to as a centralprocessing unit (CPU). Memory 2110, which may include read-only memory(ROM), random access memory (RAM), a combination of the two or any typeof device that may store information, provides instructions 2106 a anddata 2108 a to the processor 2104. A portion of the memory 2110 may alsoinclude non-volatile random access memory (NVRAM). Instructions 2106 band data 2108 b may also reside in the processor 2104. Instructions 2106b and/or data 2108 b loaded into the processor 2104 may also includeinstructions 2106 a and/or data 2108 a from memory 2110 that were loadedfor execution or processing by the processor 2104. The instructions 2106b may be executed by the processor 2104 to implement one or more of themethods and procedures 300, 700, 1800 and 1900 described above.

The eNB 2160 may also include a housing that contains one or moretransmitters 2117 and one or more receivers 2178 to allow transmissionand reception of data. The transmitter(s) 2117 and receiver(s) 2178 maybe combined into one or more transceivers 2176. One or more antennas2180 a-n are attached to the housing and electrically coupled to thetransceiver 2176.

The various components of the eNB 2160 are coupled together by a bussystem 2114, which may include a power bus, a control signal bus and astatus signal bus, in addition to a data bus. However, for the sake ofclarity, the various buses are illustrated in FIG. 21 as the bus system2114. The eNB 2160 may also include a digital signal processor (DSP)2112 for use in processing signals. The eNB 2160 may also include acommunications interface 2116 that provides user access to the functionsof the eNB 2160. The eNB 2160 illustrated in FIG. 21 is a functionalblock diagram rather than a listing of specific components.

FIG. 22 is a block diagram illustrating one configuration of a UE 2202in which systems and methods for establishing multiple radio connectionsmay be implemented. The UE 2202 includes transmit means 2258, receivemeans 2220 and control means 2224. The transmit means 2258, receivemeans 2220 and control means 2224 may be configured to perform one ormore of the functions described in connection with FIGS. 2, 6, 18 and 19above. FIG. 20 above illustrates one example of a concrete apparatusstructure of FIG. 22. Other various structures may be implemented torealize one or more of the functions of FIGS. 2, 6, 18 and 19. Forexample, a DSP may be realized by software.

FIG. 23 is a block diagram illustrating one configuration of an eNB 2360in which systems and methods for establishing multiple radio connectionsmay be implemented. The eNB 2360 includes transmit means 2317, receivemeans 2378 and control means 2382. The transmit means 2317, receivemeans 2378 and control means 2382 may be configured to perform one ormore of the functions described in connection with FIGS. 3, 7, 18 and 19above. FIG. 21 above illustrates one example of a concrete apparatusstructure of FIG. 23. Other various structures may be implemented torealize one or more of the functions of FIGS. 3, 7, 18 and 19. Forexample, a DSP may be realized by software.

The term “computer-readable medium” refers to any available medium thatcan be accessed by a computer or a processor. The term“computer-readable medium,” as used herein, may denote a computer-and/or processor-readable medium that is non-transitory and tangible. Byway of example, and not limitation, a computer-readable orprocessor-readable medium may comprise RAM, ROM, EEPROM, CD-ROM or otheroptical disk storage, magnetic disk storage or other magnetic storagedevices, or any other medium that can be used to carry or store desiredprogram code in the form of instructions or data structures and that canbe accessed by a computer or processor. Disk and disc, as used herein,includes compact disc (CD), laser disc, optical disc, digital versatiledisc (DVD), floppy disk and Blu-ray® disc where disks usually reproducedata magnetically, while discs reproduce data optically with lasers.

It should be noted that one or more of the methods described herein maybe implemented in and/or performed using hardware. For example, one ormore of the methods described herein may be implemented in and/orrealized using a chipset, an application-specific integrated circuit(ASIC), a large-scale integrated circuit (LSI) or integrated circuit,etc.

Each of the methods disclosed herein comprises one or more steps oractions for achieving the described method. The method steps and/oractions may be interchanged with one another and/or combined into asingle step without departing from the scope of the claims. In otherwords, unless a specific order of steps or actions is required forproper operation of the method that is being described, the order and/oruse of specific steps and/or actions may be modified without departingfrom the scope of the claims.

It is to be understood that the claims are not limited to the preciseconfiguration and components illustrated above. Various modifications,changes and variations may be made in the arrangement, operation anddetails of the systems, methods and apparatus described herein withoutdeparting from the scope of the claims.

What is claimed is:
 1. A method for dual connectivity by a userequipment (UE), comprising: receiving a radio resource control (RRC)connection reconfiguration message including control information for anaddition of a second set of cell(s); and performing a random access fora cell of the second set of cell(s), wherein the control informationindicate whether a dedicated random access preamble identity isincluded, a first set of cell(s) corresponds to a first Medium AccessControl (MAC) entity, and the second set of cell(s) corresponds to asecond MAC entity.
 2. A method for dual connectivity by a base station,comprising: receiving a radio resource control (RRC) connectionreconfiguration message including control information for an addition ofa second set of cell(s); and performing a random access procedure for acell of the second set of cell(s), wherein the control informationindicate whether a dedicated random access preamble identity isincluded, a first set of cell(s) corresponds to a first Medium AccessControl (MAC) entity, and the second set of cell(s) corresponds to asecond MAC entity.
 3. A user equipment (UE) for dual connectivity,comprising: a processor; memory in electronic communication with theprocessor, wherein instructions stored in the memory are executable to:receive a radio resource control (RRC) connection reconfigurationmessage including control information for an addition of a second set ofcell(s); and perform a random access for a cell of the second set ofcell(s), wherein the control information indicate whether a dedicatedrandom access preamble identity is included, a first set of cell(s)corresponds to a first Medium Access Control (MAC) entity, and thesecond set of cell(s) corresponds to a second MAC entity.
 4. A basestation for dual connectivity, comprising: a processor; memory inelectronic communication with the processor, wherein instructions storedin the memory are executable to: send a radio resource control (RRC)connection reconfiguration message including control information for anaddition of a second set of cell(s); and perform a random accessprocedure for a cell of the second set of cell(s), wherein the controlinformation indicate whether a dedicated random access preamble identityis included, a first set of cell(s) corresponds to a first Medium AccessControl (MAC) entity, and the second set of cell(s) corresponds to asecond MAC entity.